The present invention relates to an IC card and a method of fabricating the card, and more particularly, to an IC card with a built-in IC chip and a method of fabricating that card.
With the rapid development of fabricating techniques for a semiconductor chip, the size of the semiconductor chip is gradually being reduced to a size small enough to be built in a thin card, thus enabling development of a "smart card." The smart card includes a memory device for storing recorded information, an operating system, etc. The smart card is called an IC (integrated circuit) card and is also called a memory card, a chip-in-card, or an intelligent card.
Since the smart card has a built-in microprocessor semiconductor device, it is multi-functional, multi-purpose, and very secure. Because of this, the smart card has replaced existing magnetic cards and is widely used in various fields including banking, is medical service, and personal identification. The card may take the form of a telephone card, a cash card, a credit card, an I.D. card, a resident registration card, etc.
In general, the IC card includes an IC module having an IC chip and a series of connection terminals for transmitting and receiving data to and from an external device, and the IC module is generally placed in a card substrate.
Referring to FIG. 1, the conventional IC card has an IC module 14 mounted in a cavity of a card substrate 11. Card substrate 11 is generally made of synthetic resins. An over sheet layer 12 composed of synthetic resins is formed on card substrate 11. On the bottom surface of the card substrate, an inner sheet layer 13 and an under sheet layer 15 are sequentially formed.
The IC card having such a configuration has a large storage capacity, provides excellent security, and is easy to carry. For reliability reasons, it is necessary to protect the card main frame, including the mounted IC chip, against the environment when carried, i.e., from an external stress such as bending.
When the IC card is fabricated, a portion of card substrate 11 is etched to form a cavity in which IC module 14 is to be mounted. Accordingly, when the stresses due to bending are applied to the IC card, the cavity portion of the card substrate is increasingly subjected to stress and, thus, may be damaged.
Also, card substrate 11, made of synthetic resins, is prone to deformation due to heat generated from the chip or heat applied during thermal compression to adhere over sheet 12 and inner sheet layer 13 to the card substrate.
As described above, the conventional IC card may be deformed due to mechanical and thermal instability and, thus, is not reliable.